COMMEECIAI. PEODUCTIOX OF LEMON-GRASS OIL. 5 



continue to grow tkroughout the summer, it has been found that 

 after a certain size has been reached the increase in weight is less 

 rapid; hence, it is more profitable to harvest the crop at the time 

 stated and allow a new growth to develop. In the early fall of the 

 first year a second cutting can be secured. After the first year the 

 growth in the spring is more rapid and three harvests a year can be 

 obtained. Harvesting can be accomplished by the use of a mowing- 

 machine so adjusted as to cut the plants about 8 inches above the 

 ground. The cut material can be raked up with a horserake run 

 crosswise of the rows. 



In order to determine the proper stage and height at wliich the 

 plants should be cut to produce the best yield and quality of oil, a 

 number of tests were made, covering several years. In 1908 the 

 plants were cut when they were 2 feet high. They were then tied 

 in bundles, the bundles cut into tliree 8-inch lengths, and each portion 

 chstilled separately. The yield of oil obtained from each portion, 

 together with the citral content of the oils, is shown in Table I. 



Table I. — Yield cnid citral content of lemon-grass oils distilled from plants 2 feet hit/h. 



Porlion of plant, distilled. 



Yield of 

 oil. 



Per cent. 



Upper third 0. 46 



Middle third .24 



Lowest third , .10 



Citral con- 

 tent of the 

 oil.i 



Per cent. 

 70 



78 

 82 



' The ritral content throughout all the experiments was determined by the sodium-sulphite method. 



From these results, which are borne out by additional data obtained 

 in succeeding yeai-s, the conclusion is evident that close cutting will 

 not be profitable, because of the low oil content in the lower portion 

 of the plant . 



For the purpose of determining whether the hauling cost could be 

 reduced })y drying the plants before taldng them to the still, the 

 following test was made: A quantity of fresh plants was collected, 

 well niixcfl, and di\'ided into thre(> portions. The fii-st portion was 

 flislillcd green, the second portion wns exposed to the sun for several 

 hour- until the })lades were nearly dry, and the third portion was 

 (h-ied in a loft for several hom-s at 110° F. The two dried portions 

 wen- then distilled separately and the yield of oil calculated on the 

 original green weight of the material. The results secured, together 

 with the citral content of the oils, ai-<' gi\'en in Tabk^ II. 



These T-esnlts show that there was considcrahle loss of oil by diying 

 the plants. In the rase oC the sun-dried phiiits the loss on a 4-tou 

 erop would he t.S pounds of oil, or. at the prices prevailing for 101'), 

 a lo.^s of .^ii.sl, whieh would more than pay for the extra hauling 



